548 FAMILY SCOLYTIDAE 



ever, requires further careful observations to be carried out between July 



and the close of the year. The eggs of the May generation of the beetle 



are probably laid in the trees early in April by beetles which have either 



passed through the winter in the tree or have hibernated as larvae in the 



larval galleries in the bast, subsequently maturing and issuing as beetles as 



soon as the first warmth of spring makes itself felt. 



At present I have only taken this insect in full-grown and old oak trees, 



but it apparently attacks both the moru and ban oaks. 

 Damage Committed -n i . \ r ir ,i- ^i.-^ 



in the Forest danger to be reared rrom the insect is due to its 



habit of ovipositing in the bast layer of the trees. As 



has been sho\\n, the operations of the beetles and their larvae lead to 



the destruction and disappearance of the bast, and when the insects are 



numerous end in the death of the tree. In several instances the death of 



large trees examined appeared to be due directly to the attacks of this insect. 



Its greatest danger is, howe\-er, evidentl}- to be found in the fact that 

 it forms such a powerful ally to the Loranthns vcstitns parasite which infests 

 the oaks. Broad- lea\-ed trees are much more resistant to the bark-boring 

 beetle attacks than is the case with conifers, and consequenth' it is probable 

 that the oak can ordinarily hold its own against the scol\tid. 



It is essential to the latter that the bast layer of the tree should be 

 fresh and sappy; but the beetle invariably seeks out diseased trees, or 

 those which have become weakened through some cause, in which to lay its 

 eggs. The slow strangulation and consequent weakness set up in the trees 

 by the LovantJins parasite places the tree in the exact condition preferred 

 by bark beetles, and where these insects are at all numerous an attack in 

 Lomw/Ans-weakened trees may be looked upon as a foregone certaintv. 

 Once the insects have obtained a hold in a forest their powers of rapid 

 multiplication render them a pest which has to be reckoned with. 



Protective and remedial measures for safeguarding the uninfested trees 



in Naini Tal and elsewhere have been briefl\- considered 



Protection and , ,, , t ^i t li ^ ' i ■■ i-- ^ 



Remedial Measures, under the longicorn beetles Lophostcnnis liui:;clii and 



Xylotrechiis skbbingi (pp. 275, 351). It will be well, 



however, to glance at measures applicable to this insect alone, since it is 



probable that very often it infests the tree before the buprestid orcerambycid 



pests make their appearance. 



To combat these bark-borer pests adequately it becomes necessary to 

 know the exact life history of the insect, and more especially in what 

 months during the year it is in its larval stage, for it is in this stage that 

 it can be best attacked. When the tree is full of nearly full-grown larvae, 

 it should be felled and barked and the bark burnt. From the life history as 

 at present observed we know that this can be done at the end of the first 

 week in May for the grubs of the first generation and at about the end of 

 June for those of the second generation. 



Further, both as a means of discovering the number of insects in a 

 .forest and as a means of protecting that forest as well, "trap trees" should 



